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What divider ratio do you use on the THCad2 1, 32, 64, 128?

7I96S+7I85S plasma config:

 

Note that because of the use of muxed encoders, the on 7I96S  encoders
are numbered oddly = 4,6,8

The 7i96s_7i85sd.pin file in the distribution is incorrect, but the
7i96s_7i85sd.bin file is OK (it has the INM on the TB3 pins)

Note that you _can_ still use the 7I96/7i96s TB3 inputs without the INM
(GPIO works). There are be 7I96 configurations without the INM
but the 7I96S's larger FPGA means it should always fit

Hi, I'm currently building myself and hybrid Plasma/Router CNC. 

I originally chose to go with the 7i96S with 2x THCAD2 (Ohmic & Arc), but I ended up adding a 7i85S for more Steps and a 7i84D for a few more Inputs. The idea is to have everything plugged in and relying on LinuxCNC configurations to change between Plasma and Router.
I have 1 X axis, 2 Y axis, 2 Z axis (1 plasma & 1 spindle) and 1 A axis (Rotary axis).

Now, I think I need to compile my own firmware if I want the THCADs to be on the 7i96S and also support the 7i85S right? How can I do that?
Also, I looked at 7i96s_7i85sd.pin and noticed the TB3-1 to TB3-11 have None in "Sec. func" column. Was it just forgotten, or is this by design and I will have to move my Inputs to the 7i84D?

If there is any recommendations here, please go ahead. I probably should have asked before wiring the control box, but it still easy to do any modifications right now since the box is on my desk and not in use in the CNC.
Thanks!

Ok power had been applied to the hypertherm prior to testing but an hour later the power on those pins seems to be slowly dropping off like there is a cap there at the relay?

Tying in the THCad2 to the 7i96s today and noticed that pins 12 and 14 of the CPC port which are for arc ok / Transfer have power on them 14 has 18vdc and 12 has 24vdc. Kept wondering why I was getting the ARC ok LED on the 7i96s to light up. Is this normal as I was under the impression 12 and 14 were just basically part of an internal relay in the Hypertherm so technically the only power there should be what ever I supply to it?? No where in my system do I have those voltages as it is 50vdc, 12vdc and 5 vdc these power readings are also present when there is no power applied to the Hypertherm. So im guessing somehow im applying voltage to it through one of the other connections and its multiplying??

@Rod,
He mentioned several times he has a HF/HV start plasma, the THCAD manual clearly states not to use that combo.
Having cleared that cautionary tale, THCAD can work with HF/HV start as can be proven by probably 10 i have in use daily, just some care must be taken when wiring to choose a suitable point where the HF has less effect, usually at the rectifier output or at the built in HF filter/protection.
And additionally a few days back i wired a THCAD10 directly to outside connectors on a new cheap china inverter plasma with HF start, THROUGH 2 resistors and added a 0.22uF/350V capacitor across the THCAD input just to be on the safe side, and it also filters the readings a bit. Used it for 2 days, all good, probably did over 200 starts as i was tuning voltage/feed/air so made a lot of 100x10mm rectangles.
Just to be clear, do this at your own risk, any mishaps usually end badly.
A 0.1uF capacitor would be better, did not have one with such high voltage.

tommylight wrote:

How did you wire the THCAD to PLasma?
 

I did'nt yet, I just tried with the multimeter to read the arc voltage, and a simple circuit with a battery and a led to see if the reed relay was correctly activated. I'm going to wire to the THCAD today I think. I might lack the 2.5M resistor though. Could you tell me again which rating it should be ?

I am going to follow this wiring diagram (second one) for the THCAD-2 : forum.linuxcnc.org/38-general-linuxcnc-q...-questions#gallery-2

I did'nt yet, I just tried with the multimeter to read the arc voltage, and a simple circuit with a battery and a led to see if the reed relay was correctly activated. I'm going to wire to the THCAD today I think. I might lack the 2.5M resistor though. Could you tell me again which rating it should be ?

I am going to follow this wiring diagram (second one) for the THCAD-2 : forum.linuxcnc.org/38-general-linuxcnc-q...-questions#gallery-2

polskleforgeron wrote:

 I only have one question though. With the Stahlwerk's HF starts, could it fry the THCAD ? It didn't seem to affect much my multimeter when I tried it.

Also, is there a way to upload directly a video on the forum ? I'd like to show you the machine !

 

The THCAD can handle 500 volt overvoltage which is higher than your plasma cutter will generate so you won't damage it unless you connect >5v to the encoder side (Ask me how I know, 24v is enough to kill the encoder input, but I could use another encoder input on my 7i76e from the plasma firmware)

Upload your video to Youtube and link to it

I ran through PNCconfig to reset everything so I'm not sure if that made changes for me and I didnt see them, all I know is the jerkiness of the motors at idle went away after that change. I just did a dry run with one of files using the plasmac post processor in sheetcam and seemed to go well. Well except my float switch it did a touch than lift than a drop and than lift again Ill need to dial that in a little better as during the dry run it was about 1/4" off the material.

I'm still in need of reading up on the THCad2 for height control. I Asked a few questions last month and need to go back and touch base on those. cant remember what all i need to add or do to ensure it is going to work properly. but that is probably a few days out still as i need to weld in a few more supports for my waterpan.

How did you wire the THCAD to PLasma?

A big update today,I have the whole base machine working.

It goes at the speed it should, execute direct Gcode command. I had some struggle with the smallest motor on the Z axis which might be a bit underpowered and had to use only 1/4 microstepping to get enough torque from it. I think I'm gonna buy a bit more powerfull one.

I also decided I wanted to try to use the Stahlwerk before buying the Stamos. I manage to get voltage arc, On/OFF with a relay and arcOK signal with the reed relay.

I really feel more confident today in this project and have a better understanding of the whole thing. Thanks to you guys. I only have one question though. With the Stahlwerk's HF starts, could it fry the THCAD ? It didn't seem to affect much my multimeter when I tried it.

Also, is there a way to upload directly a video on the forum ? I'd like to show you the machine !
 

Slowly but steadily I'm wiring everything I need for the first test : limit switches and Y and X motors (the Z axes will be configured later with the THCAD wired in).

All the shield of the shielded cables that goes outside the box have a ground connection through the aviator connectors casing and the frame. There is room for a fifth axis If I want to add a tube cutting option later. There is 4 hole left on the left side for 2G aviator connector (emergency stop and the connection to THCAD-2 and Mesa 7i96s once I start to wire the plasma).

I feel a bit more confident now that I've started all the wiring about this THC thing.

Could someone confirm that I need :
- access to the arc voltage (which will be 1:1 ratio), to the THCAD-2 through a 2.5MOhm resistor on the negative wire
- a way to start and stop the plasma through a normal relay (via the Mesa 7i96s)
- an arcOk signal which I can access through a reed relay with the torch cable wraped three time around it (signal also read by the Mesa 7i96s) 

I'm still wondering about the Stamos or the Stahlwerk, maybe it could be worth it to try with the sthalwerk I already own now that I understand the electronic better...

I'm really enjoying this part, the machine starts to look like a real thing. I'm going slow because I'm always waiting for connectors or cable I forgot to order and I want to do it right from the begining because I know myself : if it works I will never go back to finish it cleanly.

Some pictures (if someone see a blattant mistake dont hesistate to tell me please ): 
 
 
 

Great just need to add a THCAD2.

No resistor needed, it is on the divider.